The SImvim plugin is located in main /plugins/ folder and used "globally".
The point is, you create the data cfg file that "describes" real functions for each control element using unified SImVim naming. I.e. the "Wings_Air_Heat" switch is the same for every plane.
In case if some custom plane has data "conversion" table (either embedded in our database as default or created by user) this conversion file is located in specific plane root folder ("simvim_PLANE.dat" file).
So, every time you are changing the plane, the plugin "remaps" all needed data on configuration load.